1. Field of the Invention
The present invention relates to an ion implantation system for manufacturing a semiconductor device, and more particularly, to an ion implantation system for manufacturing a semiconductor device in which the arrangement of system components is compacted to save space.
2. Background of the Related Art
In general, ion implantation equipment in an apparatus for manufacturing semiconductor devices can regulate the concentration of impurities within a range of 1014-1018 atoms/cm2. Since ion implantation technology can control impurity concentration more easily than other impurity implantation technologies such as diffusion, and since the depth of ion implantation can be performed accurately, ion implantation equipment is being more widely used as the integration of semiconductor devices increases.
A conventional ion implantation system includes an ion source, an ion extractor, an ion mass analyzer, an ion accelerator, and an end station constituted by an ion concentrator, a disk for placing a wafer thereon and a Faraday cup assembly.
High voltages of various levels must be supplied to each of the above components for ion decomposition, extraction and acceleration. As the high voltages are supplied, gas which is provided from an ion generator is converted to a plasma state. Then, electrons are extracted by an electric field formed by the applied voltage. Desired ions from among the extracted ions are refracted, accelerated, and focused to thereby implant impurity ions at an appropriate depth in the wafer.
FIG. 1 schematically depicts a conventional ion implantation system. A process of implanting impurity ions into a semiconductor device will be described referring to FIG. 1.
Impurities in a gas or solid state are provided to an ion generator 12 from an impurity supplying source (not shown), including the impurities to be ion-implanted. The ion generator 12 includes a separate power source and vacuum pump to ionize the impurities by generating a plasma.
The positive ions or negative ions generated from the ion generator 12 are extracted from the ion generator 12 through an ion extracting aperture 13 by applying an appropriate voltage to the ion extractor. The extracted positive ions or negative ions can be converted into negative ions or positive ions, respectively, in an ion converter 14 with a magnesium medium.
The impurity ions that are converted into negative ions pass through an ion mass analyzer 16 and are separated by virtue of the fact that the radius of refraction of ions will differ in a magnetic field according to the mass thereof.
The ion beam 26 then enters an ion accelerator 18 having a separate voltage source where the negative ions are accelerated to attain a high energy level. Then, the ion beam 26 passes through a focusing means, such as a Tendetron chamber 20, where it is concentrated, scanned and charge-divided for implantation into a predetermined portion of a wafer 10 located on a disk 22.
The disk 22 includes a Faraday cup assembly 24 for measuring the implantation dosage amount. The Faraday cup assembly 24 is provided with a reverse voltage for restricting secondary ions resulting from the ion implantation. A measurement meter 28 for measuring the implantation dose amount with reference to the beam current is also provided.
In the conventional ion implantation system as shown in FIG. 1, the ion mass analyzer 16 is installed such that the ion beam is refracted horizontally and all the ion implantation system component devices, from the ion generator 12 to the disk 22 where the wafer 10 is located, are installed on the same horizontal plane as the semiconductor manufacturing equipment.
Thus, the conventional ion implantation system suffers a disadvantage in that the manufacturing equipment occupies a great deal of space. This large space requirement conflicts with present desires and trends to reduce equipment size due to the high price of manufacturing space.
The present invention provides an ion implantation system for manufacturing a semiconductor device in which the equipment utilizes less manufacturing floor space.
This and other objects of the present invention are achieved by an ion implantation system, having a plurality of components installed along the path of an ion beam, for manufacturing a semiconductor device, wherein certain ones of the plurality components are arranged on a first horizontal plane and remaining ones of the plurality of components are arranged on a second horizontal plane.
The plurality of components comprising: an ion generator; an ion extractor; an ion converter; an ion mass analyzer; an ion accelerator; an ion focusing device; and an end station where a wafer is located for ion implantation, with the ion generator, the ion extractor, the ion converter, and the ion mass analyzer being arranged along the first horizontal plane, and the ion accelerator, the ion focusing device, and the end station being arranged along the second horizontal plane.
The first and second horizontal layers are vertically separated, and preferably, the first horizontal layer is vertically lower than the second horizontal layer. The ion mass analyzer is installed to operate such that ion beams passing therethrough are refracted vertically, whereby the ion beam path commences along the first horizontal plane, passes through the ion mass analyzer, is vertically refracted to the second horizontal plane, and is implanted into the wafer along the second horizontal plane.
It should be understood that both the foregoing general description and the following detailed description are explanatory and are intended to provide further explanation of the invention as claimed.